Based upon the Bergeron

air mass In meteorology, an air mass is a volume of air defined by its temperature and humidity. Air masses cover many hundreds or thousands of square miles, and adapt to the characteristics of the surface below them. They are classified according to ...

classification scheme is the Spatial Synoptic Classification system, or SSC. There are six categories within the SSC scheme: Dry Polar (similar to continental polar), Dry Moderate (similar to maritime superior), Dry Tropical (similar to continental tropical), Moist Polar (similar to maritime polar), Moist Moderate (a hybrid between maritime polar and maritime tropical), and Moist Tropical (similar to maritime tropical, maritime monsoon, or maritime equatorial). The SSC was originally created in the 1950s to improve weather forecasting, and by the 1970s was a widely accepted classification system for climatologists. The initial iteration of the SSC had a major limitation: it could only classify weather types during summer and winter season.

References

Climate and weather classification systems {{climatology-stub